Dorchester is a historic neighborhood of over six square miles in Boston, Massachusetts, United States. The town was founded by Puritans who emigrated from Dorchester, England in 1630. This dissolved municipality, Boston's largest neighborhood by far, is often divided by city planners in order to create two planning areas roughly equivalent in size and population to other Boston neighborhoods. It is named after the town of Dorchester in the English county of Dorset, from which Puritans emigrated on the ship Mary and John, among others and is today sometimes nicknamed "Dot" by its residents. Dorchester, now covering a geographic area approximately equivalent to the city of Cambridge, Massachusetts, was founded a few months before the city of Boston in 1630. It was still a primarily rural town and had a population of 12,000 when it was annexed to Boston in 1870. Railroad and streetcar lines brought rapid growth, increasing the population to 150,000 by 1920. In the 2010 Census the population was 92,115, although the city's previously mentioned artificial planning boundaries make the neighborhood's population size difficult to assess - it is likely closer to 120,000. Dorchester as a separate municipality would rank among the top five Massachusetts cities. It has a very diverse mix of Eastern Europeans, African Americans, European Americans, Irish American immigration, Caribbean Americans, Latinos, and East and Southeast Asian Americans. Recently, there has been an influx of young professionals, gay people, and working artists to the neighborhood, adding to its diversity.